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lowest beds, east of the salines at Moutiers,
I discovered the distinct impression of
small cardites, and one shell, which an
eminent conchologist, to whom I shewed
it, supposed to be a patella. The great
degree of induration which the limestone
in this valley has assumed, seems to have
nearly obliterated all traces of organic existence,
as they are rarely to be discovered.
Where the limestone approaches the gypsum,
it contains, like the gypsum, an intermixture
of soft talc or steatite, and it is
also interstratified with schistose beds of
soft talc, and beyond the baths it appears
to cover a talcous slate, that approaches to
the nature of oolite. This limestone sometimes
reposes upon dark bituminous schist,
and sometimes on a coarsely aggregated
rock, which may be called either sandstone
or grey-wacke, according to the views of
different geologists. If it can be proved
that rocks formerly regarded as the very
oldest transition rocks are found posterior
to upper secondary strata, we shall have
little difficulty in admitting, that grey-wacke
may be found there also ; and if the upper
\ es in Savoy assume the
mineralogical characters of our old limestones,
which they assuredly do, we can
have no hesitation in admitting, that the
associated sandstone strata, may assume the
characters of grey-wacke.
There is one mass of a hard siliceous
rock, containing fragments of the older
rocks, at the bottom of the valley, near
the baths, but I am inclined to believe that
its position is what geologists call uncon-
formable.
The gypsum in this valley, I am prepared
to show, alternates with the calcareous
strata. This gypsum has been
described by M. Brochant, as lying im-
conformably over all the other rocks in the
Tarentaise. I have the greatest respect for
the talents of this eminent professor, and
without positive proof, I should not have;
presumed to differ from him on the subject,
as he formerly resided for some time at
Moutiers, and had of course an opportunity
of examining the country.
Dr. Hybord, the physician at Brida, had
formerly paid attention to mineralogy:
when speaking to me of the gypsum, he
said that it invariably covered the other
rocks “ coimne une chemiseF The question
respecting the position of the gypsum in
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